Data Integrity Validation in Storage Systems

1. A data integrity evaluation method comprising: receiving a request for performing an operation on a first data chunk from among N data chunks respectively written across N storage mediums, wherein a recovery chunk recorded on a second storage medium independent of said N storage mediums is associated with said N data chunks such that recovery information included in said recovery chunk is calculated based on collective value of data stored in said N data chunks, wherein the recovery chunk is associated with a first validation appendix comprising a set of N validation information, wherein each of the N validation information corresponds to one of the N data chunks and each validation information is usable to independently validate the respective data chunk; attempting to validate the first data chunk based on first validation information associated with the first data chunk; and in response to not being able to validate the first data chunk based on the first validation information, examining secondary validation information associated with one or more data chunks other than the first data chunk to determine whether the first data chunk is valid.

2. The method of claim 1 , wherein the secondary validation information is stored in the first validation appendix on the second storage medium in association with the recovery chunk.

3. The method of claim 1 , wherein the secondary validation information is stored on one or more of the N storage mediums in association with one or more data chunks other than the first data chunk.

4. The method of claim 1 , wherein examining the secondary validation information, in response to not being able to validate the first data chunk based on the first validation information, comprises: examining N−1 validation information in the first validation appendix against the corresponding other N−1 data chunks to determine whether the first data chunk is valid.

5. The method of claim 1 , wherein examining the secondary validation information, in response to not being able to validate the first data chunk based on the first validation information, comprises: examining a second validation appendix including second validation information associated with a second data chunk to determine whether the first data chunk is valid.

6. The method of claim 1 , further comprising: in response to determining that the first data chunk is invalid, reconstructing the first data chunk based on the recovery information in the recovery chunk and based on the value of the other N−1 data chunks.

7. The method of claim 1 , further comprising: in response to determining that the first data chunk is valid, updating the recovery chunk based on the collective value of the N data chunks.

8. The method of claim 1 , further comprising: in response to determining that the first data chunk is valid, updating the validation information in the first validation appendix based on the corresponding values of the N data chunks.

9. The method of claim 1 , wherein the recovery information is usable to reconstruct one or more of said N data chunks.

10. The method of claim 1 wherein the recovery chunk is one of a plurality of recovery chunks.

11. The method of claim 10 , wherein examining the secondary validation information, in response to not being able to validate the first data chunk based on the first validation information, comprises: examining a second validation information associated with a second recovery chunk to determine whether the first data chunk is valid.

12. A system for data integrity evaluation comprising: N storage mediums on which data is written in a first data chunk from among N data chunks respectively written across the N storage mediums; a second storage medium independent of said N storage mediums, wherein a recovery chunk is recorded on said second storage medium, wherein the recovery chunk is associated with said N data chunks such that recovery information included in said recovery chunk is calculated based on collective value of data stored in said N data chunks, wherein the recovery chunk is associated with a first validation appendix comprising a set of N validation information, wherein each of the N validation information corresponds to one of the N data chunks and each validation information is usable to independently validate the respective data chunk, wherein a first validation information is associated with the first data chunk and a secondary validation information is associated with one or more data chunk other than the first data chunk; a controller for receiving a request for performing an operation on the first data chunk from among said N data chunks, wherein the controller attempts to validate the first data chunk based on the first validation information, and wherein the controller, in response to not being able to validate the first data chunk based on the first validation information, examines the secondary validation information to determine whether the first data chunk is valid.

13. The system of claim 12 , wherein the secondary validation information is stored in the first validation appendix on the second storage medium in association with the recovery chunk.

14. The system of claim 12 , wherein the secondary validation information is stored on one or more of the N storage mediums in association with one or more data chunks other than the first data chunk.

15. The system of claim 12 , wherein examining the secondary validation information, in response to not being able to validate the first data chunk based on the first validation information, comprises: the controller examining N−1 validation information in the first validation appendix against the corresponding other N−1 data chunks to determine whether the first data chunk is valid.

16. The system of claim 12 , wherein examining the secondary validation information, in response to not being able to validate the first data chunk based on the first validation information, comprises: the controller examining a second validation appendix including second validation information associated with a second data chunk to determine whether the first data chunk is valid.

17. The system of claim 12 , further comprising: in response to determining that the first data chunk is invalid, the controller reconstructing the first data chunk based on the recovery information in the recovery chunk and based on the value of the other N−1 data chunks.

18. The system of claim 12 , further comprising: in response to determining that the first data chunk is valid, the controller updating the recovery chunk based on the collective value of the N data chunks.

19. The system of claim 12 , further comprising: in response to determining that the first data chunk is valid, the controller updating the validation information in the first validation appendix based on the corresponding values of the N data chunks.

20. The system of claim 12 , wherein the recovery information is usable to reconstruct one or more of said N data chunks.

21. The system of claim 12 wherein the recovery chunk is one of a plurality of recovery chunks.

22. The system of claim 21 , wherein examining the secondary validation information, in response to not being able to validate the first data chunk based on the first validation information, comprises: the controller examining a second validation information associated with a second recovery chunk to determine whether the first data chunk is valid.

23. A computer program product comprising a non-transient computer readable storage medium having a computer readable program stored thereon, wherein execution of the computer readable program on a computer causes the computer to: receive a request for performing an operation on a first data chunk from among N data chunks respectively written across N storage mediums, wherein a recovery chunk recorded on a second storage medium independent of said N storage mediums is associated with said N data chunks such that recovery information included in said recovery chunk is calculated based on collective value of data stored in said N data chunks, wherein the recovery chunk is associated with a first validation appendix comprising a set of N validation information, wherein each of the N validation information corresponds to one of the N data chunks and each validation information is usable to independently validate the respective data chunk; attempt to validate the first data chunk based on first validation information associated with the first data chunk; and in response to not being able to validate the first data chunk based on the first validation information, examine secondary validation information associated with one or more data chunks other than the first data chunk to determine whether the first data chunk is valid.

24. The computer program product of claim 23 , wherein the secondary validation information is stored in the first validation appendix on the second storage medium in association with the recovery chunk.

25. The computer program product of claim 23 , wherein the secondary validation information is stored on one or more of the N storage mediums in association with one or more data chunks other than the first data chunk.

26. The computer program product of claim 23 , wherein examining the secondary validation information, in response to not being able to validate the first data chunk based on the first validation information, further comprises: examining N−1 validation information in the first validation appendix against the corresponding other N−1 data chunks to determine whether the first data chunk is valid.

27. The computer program product of claim 23 , wherein examining the secondary validation information, in response to not being able to validate the first data chunk based on the first validation information, further comprises: examining a second validation appendix including second validation information associated with a second data chunk to determine whether the first data chunk is valid.

28. The computer program product of claim 23 , wherein the computer readable program when executed on a computes further causes that computer to: reconstruct the first data chunk based on the recovery information in the recovery chunk and based on the value of the other N−1 data chunks, in response to determining that the first data chunk is invalid.

29. The computer program product of claim 23 , wherein the computer readable program when executed on a computes further causes that computer to: update the recovery chunk based on the collective value of the N data chunks, in response to determining that the first data chunk is valid.

30. The computer program product of claim 23 , wherein the computer readable program when executed on a computes further causes that computer to: update the validation information in the first validation appendix based on the corresponding values of the N data chunks, in response to determining that the first data chunk is valid.